"Remove from phoneline before opening battery compartment".
Even if 50V was dangerous (which it isn't), if 50V got from the phoneline into the battery compartment, I think a shock would be the least of your problems.
ever heard of lighting strikes?
If someone happens to call you whilst you have your fingers in it then it'll be more like 150V. Also, they can't guarantee that there won't be surges on the line into thousands of volts. It's a looong time since I designed phone-line connected kit but ISTR anything touchable needed at least 3KV of isolation from the line.
Cheers,
Colin.
into the battery compartment, I think a shock would be the least of your p roblems.
The lowest voltage someone was killed was 40 volts.
into the battery compartment, I think a shock would be the least of your problems.
References?
What's the chances of that during a battery change?
And why do you think you need to be touching the contacts for lightning to get to you?
AFAIK it's -50V, +50V once a secondish.
3kV into a battery and you'd need more than a battery cover to protect you.
into the battery compartment, I think a shock would be the least of your problems.
I saw something once about 9 volts from a multimeter.....
Weeds out the weak I guess...
More bollocks. Ringing is around 80 V at 25 Hz (in the UK).
Near enough.
Wrong. It can go up to 150V RMS depending on line conditions.
Once per second? Now you're just being silly.
Why? What do you imagine will happen? A battery can happily be elevated to any voltage you like WRT earth and not even notice.
Cheers,
Colin.
Depending on the REN (most modern phones have a real REN of near zero) it can be as much as 150V. I think 80V may be the minimum spec. Also, the 50V DC line voltage may or may not still be superimposed during ringing.
Cheers,
Colin.
Ooooh scary. Anyway, it would have to ring at the precise moment you are changing the battery, AND have a fault which caused the 150V to be in the battery compartment.
That's about how often the phone makes a ringing sound.
What has earth to do with it? How many people will be earthed while changing a telephone battery?
BT SIN 351 Issue 4.5 states between 40 and 100 V AC RMS at the NTE. So the 100 V RMS gives a peak approaching 150 V
True.
Nope 150 V peak(ish), max ringing is 100 V RMS. There may be a 50 V DC offset with that or not. 150 V RMS plus a 50 V DC offset gives you about
260 V peak...
Nope, the cadence of the 25 Hz pulses is: 0.4 s on, 0.2 s off, 0.4 s on,
2 s off.
So I guessed 1s instead of 0.6s. Close enough.
Sounds about right. I thought it was 150V RMS but it was [mumble] years ago...
Cheers,
Colin.
Read carefully.
"the 25Hz pulses".
Andy
AC is less harmful.
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